High-pressure steam boiler



June 4, 1 929. 4 o. H. HARTMANN ET AL 1,716,053

HIGH PRESURE STEAM BOILER Filed Jan. 2, 1923 PETER filo/455 1 I a Patented June 4, 1929.

"UNITED STATES PATENT OFFICE.

o'rro HERMAN H ARTMANN, or CA SSEL-WILHELMSHOHE, AND PETER rnomsnn, or CASSEL, ennmnnxyassrenons '10 scnmm'r'scnn HEISSDAMPF-GESELLSCHAFT M. B. 3., OF GASSEL-WILHELMSHOH E, GERMANY, A CORPORATION OF GERMANY.

nren-rnnss'unn s'rnaiu BOILER.

Application filed January 2, 1923, Serial No. 610,319, and in Germany January 5, 1922.

Our invention relates to high pressure steam boilers, and has for its object to provide an arrangement afiording protection to the drums or containers filled with water,

' 5 or withwater and steam, which form part of the boilers, particularly in cases 'where' such drums or containers are intended to hold steam at high pressures, say 30 atmospheres and above.

There is still a certain amount of prejudice among manufacturers of steam boilers against the use of high pressures, such as 30 atmospheres and over, for the reason that relatively high temperatures are involved when using such high pressures and fear has been expressed repeatedly that the strength of the material would suffer a substantial and dangerous reduction, when exposed during operation-of the boiler, to temperatures such as occur with said pressures, which temperatures are very close to those at which so-called blue heat causes the material to become brittle. Such range of blue heat causing brittleness lies between 250 and 5'300 C. Iron used in the construction of boilers according to theusual requirements will frequently undergo a great loss of strength at such temperatures. The brittle ness'resulting from the use of such. temperatures is particularly noticeable when the material has previously been worked in a cold condition. It is true that boiler drums or containers adapted to withstand operating pressures of theo'rder mentioned above can be forgedwithout seams,-or at least composed of seamless sections welded together, the containers being subsequently heated to incandescence, so that, during the operation of the boiler only the stresses caused by 'steam pressure will occur 'in the solid portionsof the drum wall: At those points, however, where the water tubes are connected with the drum by beading or expanding them in suitable openings of the drum, addltional stresses occur, owing to the operation of fastening the tube ends, and in view of these additional stresses, it is desirable to provide means for protecting the material of the drum against the influence of strong heating from one side. According to our present invention, this result is obtained by providing, in conjunction with the water tubes, bracing or guiding members therefor which are so constructed that, while permitting contact with the combustion gases.

longitudinal expansion or contraction of the water tubes resulting from changes in temperature, they prevent vibration or lateral movement thereof, thus .guarding against the ends becoming loose; while, preferably, the outer surface of the drum wall is recessed ad'acent to the tube receiving openings in or er to prevent the transmission to such surface of any strains from the tubes, thus preventing the. formation of surface cracks. Thus, one of the objects of our invention is to anchor or brace the water tubes while allowmgthem to expand or contract in response to rising or falling temperature. Another object of our inventio is. to form, at a distance from the wall 0 the drum, a barrier or partition protecting such container and particularly that portion of it which receives the tube ends, against direct preferred form of our invention, this -partition or barrier, which'at the same time forms an anchoring means for the water tubes, is composed of carrying members located between the rows of water tubes and intermediate membersfitted on the tubes between said carrying members, the carrying members and the intermediate members having mating tapering or wedge-shaped surfaces. Thus, the intermediate members will by their own weight become wedged and-sc Inthe' curely anchored by friction to the carrying members and to the water tubes, thus holding the latter steady. Longitudinal expaIi-' sion 'of the tubes, due to changes of temperature is however freely permitted, since the intermediate members are capable of following relatively large longitudinal movements, if they 'occtlr slowly, Rapid vibratory movements of the water tubes are, however, absorbed or stopped by said carrying mem-' bers and intermediate members, so that such vibrations are not transmitted to the points at which the tube ends touch the walls of the container or drum. In this manner, the material of the drum wall is protected against excessive stresses. v

By providing a barrier or partition between the drum and the path of the combustion gases, at a distance from said drum, we form an air space between the wall of the drum and the path of the combustion gases, on the side where the water tubes connect with saiddrum. This airspace has two useful functions: First, it acts as an insulator to minimize the transmission of heat from the combustion gases to the nearest portion of the drum wall and thus protects said wall portion against excessive heating and resulting stresses. Another advantage of this arrangement resides in the fact that it enables the joints where the tube ends are fastened to the drum wall, to be inspected from the outside, which would not be possible if said tube ends were exposed directly to the combustion gases or if a layer of asbestos or other heat insulating material were placed directly in contact with the said portion of the drum.

A preferred and satisfactory embodiment of our present invention is'illustrated by the accompanying drawings, in which Fig. 1 is a Vertical section of a boiler embodying our invention; Fig. 2 is a partial vertical section of the upper portion of Fig. 1 on an enlarged scale; Fig. 3 is a substantially vertical section taken at right angles to the plane of Fig. 2; Fig. 4 is a partial plan view of the construction and Fig. 5 is a detail view showing a specific way of fastening the upper ends of the water tubes to the lower wall of the steam and water drum.

A indicates the upper drum containing water and steam, while B are the lower drums containing water and connected with the upper drum by the water tubes 0. At D we have indicated a grate for burning fuel, the combustion gases of which heat the boiler in substantiallythe well known man- 'ner. On the boiler setting E in the neighborhood of the container or drum A, we have shown supports f on which rest the ends of the carrying members (Z running transversely of the drum between adjacent rows of water tubes C. These carrying vmembers are roof-shaped, that is "to say,

they taper upwardly, and on their converging surfaces are adapted to rest the correspondingly inclined mediate members e. These also extend longitudinally between the rows of tubes and are recessed as shown best in Fig. 4, to fit partly around the water tubes (3. Figs. 3 and 4 also show that adjacent intermediate members (1 are not in contact with each other but only with the intervening spaced carrying members (l. lVhile we do not restrict ourselves to this particular arrangement, we consider it preferable, as it allows the intermediate members e to adjust themselves more readily to their proper positions, in which they are seated upon the inclined surfaces of the carrying members d.

I It will be seen that the construction of the protecting wall composed of the members d, e, allows the water tubes 0 to expand or contract as required with changes of temperature. Such movements, however, and particularly those resulting from vibrations,

surfaces of the interwhich would tend to loosen the attached upper ends of the water tubes Care prevented by the said protecting wall, which holds the water tubes securely against lateral movement. The protecting wall further prevents the combustion gases from acting directly on the attached upper ends of the water tubes C and thus protects the joints of said tubes with the drum A against ex cessive heat strains. Furthermore, as we have mentioned hereinbefore, an insulating air space F is produced by the arrangement of the protecting wall at a distance below the drum A and this space not only further prevents the transmission of excessive heat to the lower wall of the drum A but also,

offers the advantage of permitting inspection ofthe joints at the upper ends of the water tubes. I

The manner of connecting the upper ends of the water tubes with the wall of the drum .A is shown more-clearly in Figs. 2 and 5..

The openings receiving said tube ends are recessed not only as usual on the inside of the drum wall but also on the outside thereof, so that the tube ends are not in contact with the outer surface of said wall but only along the middle or central portion. At It, we have indicated the recesses at the outer ends-of the tube-receiving openings, showing 7 clearly that there is no contact between the water tubes 0 and the outer surface of the wall of the drum A at these recesses. This ill) particular construction of the joint between pletely preventing access of the combustion gases to the lower surface of the drum A and to the insulating air space F.

As shown in Fig. 1., a protecting wall of the same character as that described specifically in its relation to the upper drum A may be provided adjacent to each of the lower drums B, to form an air-space F between the upper portion of such lower drum and the path of the combustion gases. The lower ends of the tubes C may be secured to said drums B in the same manner and with the same advantages as described in connection with the fastening of the upper tube ends.

Various changes and modifications in the specific form shown and described may be made within the scope of the claims with.- gut departing from the spirit of our inven- We claim as our invention:.

1. In a high pressure boiler, a drum, a furnace for said boiler, water tubes connected with said drum and arranged in rows, carrying members arranged transversely of thedrum between said rows and provided with wedge-shaped surfaces facing toward the drum, and intermediate members having tapered surfaces for engagement with the corresponding surfaces of the said carrying members and also provided wtih recesses to fit the said water other, each of said intermediate members having on one side a recessed surface to fit a row of water tubes and on the other side an inclined surface to fit the tapering carrying member.

3. In a high-pressure boiler, a drum, water tubes the ends of which are connected with said drum, said tubes being in contact with the drum wall only at a portion of its thickness, a furnace for said boiler, and a device extending transversely of the said tubes to prevent vibration thereof, said device engag- ,ing the tubes between the furnace and the drum and holding said tubes against lateral movement while allowing them to expand longitudinally in response to temperature changes. J 4. In a-' high-pressure boiler, a drum, water tubes the ends of which are connected with said dram, said tubes being in contact with the drum only at-the middle portion of its thickness, a furnace for said boiler, and a device extending transversely of the said tubes to prevent vibration thereof, said device engaging the tubes between the furnace and the drum and holding-said tubes against lateral movement while allowing them to expand longitudinally in response to temperature changes,

5. In a high-pressure boiler, a drum, water tubes the ends of which are connected with said drum, the latter being provided in its outer surface with recesses around said tubes so that the tubes are out of contact with the drum along the outer portion of its thickness, a furnace for said boiler, and a device extending transversely of the said tubes between the furnace and the drum and holding said tubes against lateral movement while allowing them to expand longitudinally in response to temperature changes. 6. In a high-pressure boiler, a drum having openings which are of least diameter at the middle portion of the thickness of the drum wall and enlarged toward both faces of the drum wall, water tubes the ends of which are fitted into said openings to engage said portions of least diameter, but out of contact with said enlarged portions, a furnace for said boiler, and a device extending transversely of the said tubes to prevent vibration thereof, said device engaging the tubes between the furnace and the drum and holding said tubes against lateral movement while allowing them to expand longitudinally in response to tempertaure changes.

7. In a high pressure boiler, a drum, a.

furnace for said boiler, water tubes con nected with said drum, carrying members extending between said tubes and providedwith wedge-shaped surfaces facing toward the drum, and intermediate members having tapered surfaces for engagement with the corresponding surfaces of said carrying members and also provided with recesses to fit said water tubes.

8. In a high pressure boiler, adrum, :1

furnace for said boiler, water tubes connected with said drum, tapered carrying members extending between said tubes, and intermediate members extending lengthwise of said carrying members between said tubes and out of contact with each other, each' of said intermediate members having on one side a recessed surface to fit sundryof said water tubes and on the other side an in clined surface to fit the adjoining tapered carrying member. f

9. In a high pressure boiler, a drum, a furnace for said boiler, water tubes connected with said drum, carrying members extending between said tubes 'and provided with wedge-shaped surfaces facing toward the drum, and intermediate members having tapered surfaces for engagement with the corresponding surfaces of said carrying.

members and cooperating with the tubes to form a baflie for the drums.

OTTO HERMAN HARTMANNJ PETER THOMSEN. 

